The present invention relates to a mounting disk for the fixation of loosely installed sealing sheets of a synthetic resin, wherein the mounting disk can be attached to a sub-structure, such as a roof, e.g. a trapezoidal roof, by means of a screw passed through the mounting disk.
Such mounting disks have been disclosed, for example, in DOS's [German Laid-Open Unexamined Applications] 1,658,883 and 2,300,798, respectively.
FIG. 1 of the drawings of this application shows a utilization of a mounting disk for a trapezoidal roof with a synthetic resin sealing sheet laid loosely thereon. The roof construction 10 consists of the trapezoidal metal sheet 11 on which the thermal insulating layer 12 is loosely placed. The thermal insulating layer is composed of individual heat insulating panels; the mounting disk 15 in the form of a sheet-metal disk with a synthetic resin coating 18 on the topside is provided in each case on the butt joints of these panels. The mounting disk is equipped with a central bore through which a fastening screw 14 is passed and threadedly attached through the heat insulating layer 12 to the substructure 11.
The synthetic resin sealing sheets 17 are laid over the heat insulation 12 and the mounting disks 15 and affixed to the synthetic resin coating 18 of the mounting disk 15, for example by means of gluing, solution welding, or high-frequency welding. It has now been found that, for example, in case of high wind suction forces, the roofing sheet can be forced upward through the fastening screws and/or the screw head can even be pressed through the sealing sheets. Especially in case of lightweight roofs, such as trapezoidal roofs, for example, wherein movements of the supporting substructure may also occur, for instance due to vibrations, the fastening screws 14 can unturn and thus endanger the entire roof covering and the roof sealing sheets. Since this uprising of the fastening screws by unturning occurs particularly in case of vibrations and under wind loads, the screws must be repeatedly tightened. During such operations, damage to the sealing sheet can occur, in particular.
The present invention is based on the object of preventing this uprising of the fastening screws by excluding an unturning motion of the fastening screw. This is accomplished in accordance with the invention by attaching a blocking means at the mounting disk to prevent an unturning of the fastening screw passed through the mounting disk and connected to the substrate. This attachment can be releasable or fixed, movable or immobile according to different preferred embodiments of the invention.
The blocking means can be mounted to be rotatable in certain embodiments so that it is possible to uncover the central area of the mounting disk with the bore for the fastening screw in order to introduce the latter. Advantageously, a leaf spring is provided as the blocking means; this spring being bent away at one end vertically toward the mounting disk for engaging the topside slot of the head of the fastening screw. For the preferred field of application, the blocking means is made of a corrosion-resistant material, for example spring steel. The leaf spring exerts a constant pressure on the inserted fastening screw so that an unturning of the fastening screw, for example in case of vibrations, is impossible. Based on the length of the leaf spring, as well as its configuration, a correspondingly high spring force, i.e., retaining force, can be exerted.
It is also contemplated to fix the leaf spring in position at a point of the mounting disk by means of tongues [lugs] in certain embodiments, wherein the tongues are formed by bending them upwardly from the mounting disk.
However, other embodiments are contemplated where the blocking means consist of a metal plate preferably laminated on both sides with synthetic resin film and formed with a projecting edge for engagement into the head of the screw. This blocking means can then be fixed after engagement on the mounting disk, for example, by solution welding, gluing, welding, or the like.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration, several embodiments in accordance with the present invention.